A popular science article on recent progress in organ engineering: "Implanting such a 'bioartificial' organ would be a first-of-its-kind procedure for the field of regenerative medicine, which for decades has been promising a future of ready-made replacement organs - livers, kidneys, even hearts - built in the laboratory. For the most part that future has remained a science-fiction fantasy. Now, however, researchers like Dr. Macchiarini are building organs with a different approach, using the body's cells and letting the body itself do most of the work. ... So far, only a few organs have been made and transplanted, and they are relatively simple, hollow ones - like bladders and [windpipes] ... But scientists around the world are using similar techniques with the goal of building more complex organs. At Wake Forest University in North Carolina, for example, where the bladders were developed, researchers are working on kidneys, livers and more. Labs in China and the Netherlands are among many working on blood vessels. The work of these new body builders is far different from the efforts that produced artificial hearts decades ago. Those devices, which are still used temporarily by some patients awaiting transplants, are sophisticated machines, but in the end they are only that: machines. Tissue engineers aim to produce something that is more human. They want to make organs with the cells, blood vessels and nerves to become a living, functioning part of the body. Some, like Dr. Macchiarini, want to go even further - to harness the body's repair mechanisms so that it can remake a damaged organ on its own."